2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.156 2002/01/05 10:43:40 markus Exp $");
57 #include "pathnames.h"
63 * Pointer to an array containing all allocated channels. The array is
64 * dynamically extended as needed.
66 static Channel **channels = NULL;
69 * Size of the channel array. All slots of the array must always be
70 * initialized (at least the type field); unused slots set to NULL
72 static int channels_alloc = 0;
75 * Maximum file descriptor value used in any of the channels. This is
76 * updated in channel_new.
78 static int channel_max_fd = 0;
81 /* -- tcp forwarding */
84 * Data structure for storing which hosts are permitted for forward requests.
85 * The local sides of any remote forwards are stored in this array to prevent
86 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
87 * network (which might be behind a firewall).
90 char *host_to_connect; /* Connect to 'host'. */
91 u_short port_to_connect; /* Connect to 'port'. */
92 u_short listen_port; /* Remote side should listen port number. */
95 /* List of all permitted host/port pairs to connect. */
96 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98 /* Number of permitted host/port pairs in the array. */
99 static int num_permitted_opens = 0;
101 * If this is true, all opens are permitted. This is the case on the server
102 * on which we have to trust the client anyway, and the user could do
103 * anything after logging in anyway.
105 static int all_opens_permitted = 0;
108 /* -- X11 forwarding */
110 /* Maximum number of fake X11 displays to try. */
111 #define MAX_DISPLAYS 1000
113 /* Saved X11 authentication protocol name. */
114 static char *x11_saved_proto = NULL;
116 /* Saved X11 authentication data. This is the real data. */
117 static char *x11_saved_data = NULL;
118 static u_int x11_saved_data_len = 0;
121 * Fake X11 authentication data. This is what the server will be sending us;
122 * we should replace any occurrences of this by the real data.
124 static char *x11_fake_data = NULL;
125 static u_int x11_fake_data_len;
128 /* -- agent forwarding */
132 /* Name and directory of socket for authentication agent forwarding. */
133 static char *auth_sock_name = NULL;
134 static char *auth_sock_dir = NULL;
136 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 static int IPv4or6 = AF_UNSPEC;
140 static void port_open_helper(Channel *c, char *rtype);
142 /* -- channel core */
145 channel_lookup(int id)
149 if (id < 0 || id > channels_alloc) {
150 log("channel_lookup: %d: bad id", id);
155 log("channel_lookup: %d: bad id: channel free", id);
162 * Register filedescriptors for a channel, used when allocating a channel or
163 * when the channel consumer/producer is ready, e.g. shell exec'd
167 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
168 int extusage, int nonblock)
170 /* Update the maximum file descriptor value. */
171 channel_max_fd = MAX(channel_max_fd, rfd);
172 channel_max_fd = MAX(channel_max_fd, wfd);
173 channel_max_fd = MAX(channel_max_fd, efd);
175 /* XXX set close-on-exec -markus */
179 c->sock = (rfd == wfd) ? rfd : -1;
181 c->extended_usage = extusage;
183 /* XXX ugly hack: nonblock is only set by the server */
184 if (nonblock && isatty(c->rfd)) {
185 debug("channel %d: rfd %d isatty", c->self, c->rfd);
187 if (!isatty(c->wfd)) {
188 error("channel %d: wfd %d is not a tty?",
195 /* enable nonblocking mode */
207 * Allocate a new channel object and set its type and socket. This will cause
208 * remote_name to be freed.
212 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
213 int window, int maxpack, int extusage, char *remote_name, int nonblock)
218 /* Do initial allocation if this is the first call. */
219 if (channels_alloc == 0) {
222 channels = xmalloc(channels_alloc * sizeof(Channel *));
223 for (i = 0; i < channels_alloc; i++)
225 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
227 /* Try to find a free slot where to put the new channel. */
228 for (found = -1, i = 0; i < channels_alloc; i++)
229 if (channels[i] == NULL) {
230 /* Found a free slot. */
235 /* There are no free slots. Take last+1 slot and expand the array. */
236 found = channels_alloc;
237 channels_alloc += 10;
238 debug2("channel: expanding %d", channels_alloc);
239 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
240 for (i = found; i < channels_alloc; i++)
243 /* Initialize and return new channel. */
244 c = channels[found] = xmalloc(sizeof(Channel));
245 memset(c, 0, sizeof(Channel));
246 buffer_init(&c->input);
247 buffer_init(&c->output);
248 buffer_init(&c->extended);
249 chan_init_iostates(c);
250 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
254 c->local_window = window;
255 c->local_window_max = window;
256 c->local_consumed = 0;
257 c->local_maxpacket = maxpack;
259 c->remote_name = remote_name;
260 c->remote_window = 0;
261 c->remote_maxpacket = 0;
266 c->single_connection = 0;
267 c->detach_user = NULL;
268 c->input_filter = NULL;
269 debug("channel %d: new [%s]", found, remote_name);
274 channel_find_maxfd(void)
279 for (i = 0; i < channels_alloc; i++) {
282 max = MAX(max, c->rfd);
283 max = MAX(max, c->wfd);
284 max = MAX(max, c->efd);
291 channel_close_fd(int *fdp)
293 int ret = 0, fd = *fdp;
298 if (fd == channel_max_fd)
299 channel_max_fd = channel_find_maxfd();
304 /* Close all channel fd/socket. */
307 channel_close_fds(Channel *c)
309 debug3("channel_close_fds: channel %d: r %d w %d e %d",
310 c->self, c->rfd, c->wfd, c->efd);
312 channel_close_fd(&c->sock);
313 channel_close_fd(&c->rfd);
314 channel_close_fd(&c->wfd);
315 channel_close_fd(&c->efd);
318 /* Free the channel and close its fd/socket. */
321 channel_free(Channel *c)
326 for (n = 0, i = 0; i < channels_alloc; i++)
329 debug("channel_free: channel %d: %s, nchannels %d", c->self,
330 c->remote_name ? c->remote_name : "???", n);
332 s = channel_open_message();
333 debug3("channel_free: status: %s", s);
337 shutdown(c->sock, SHUT_RDWR);
338 channel_close_fds(c);
339 buffer_free(&c->input);
340 buffer_free(&c->output);
341 buffer_free(&c->extended);
342 if (c->remote_name) {
343 xfree(c->remote_name);
344 c->remote_name = NULL;
346 channels[c->self] = NULL;
351 channel_free_all(void)
355 for (i = 0; i < channels_alloc; i++)
356 if (channels[i] != NULL)
357 channel_free(channels[i]);
361 * Closes the sockets/fds of all channels. This is used to close extra file
362 * descriptors after a fork.
366 channel_close_all(void)
370 for (i = 0; i < channels_alloc; i++)
371 if (channels[i] != NULL)
372 channel_close_fds(channels[i]);
376 * Stop listening to channels.
380 channel_stop_listening(void)
385 for (i = 0; i < channels_alloc; i++) {
389 case SSH_CHANNEL_AUTH_SOCKET:
390 case SSH_CHANNEL_PORT_LISTENER:
391 case SSH_CHANNEL_RPORT_LISTENER:
392 case SSH_CHANNEL_X11_LISTENER:
393 channel_close_fd(&c->sock);
402 * Returns true if no channel has too much buffered data, and false if one or
403 * more channel is overfull.
407 channel_not_very_much_buffered_data(void)
412 for (i = 0; i < channels_alloc; i++) {
414 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
417 buffer_len(&c->input) > packet_get_maxsize()) {
418 debug("channel %d: big input buffer %d",
419 c->self, buffer_len(&c->input));
423 if (buffer_len(&c->output) > packet_get_maxsize()) {
424 debug("channel %d: big output buffer %d > %d",
425 c->self, buffer_len(&c->output),
426 packet_get_maxsize());
434 /* Returns true if any channel is still open. */
437 channel_still_open(void)
442 for (i = 0; i < channels_alloc; i++) {
447 case SSH_CHANNEL_X11_LISTENER:
448 case SSH_CHANNEL_PORT_LISTENER:
449 case SSH_CHANNEL_RPORT_LISTENER:
450 case SSH_CHANNEL_CLOSED:
451 case SSH_CHANNEL_AUTH_SOCKET:
452 case SSH_CHANNEL_DYNAMIC:
453 case SSH_CHANNEL_CONNECTING:
454 case SSH_CHANNEL_ZOMBIE:
456 case SSH_CHANNEL_LARVAL:
458 fatal("cannot happen: SSH_CHANNEL_LARVAL");
460 case SSH_CHANNEL_OPENING:
461 case SSH_CHANNEL_OPEN:
462 case SSH_CHANNEL_X11_OPEN:
464 case SSH_CHANNEL_INPUT_DRAINING:
465 case SSH_CHANNEL_OUTPUT_DRAINING:
467 fatal("cannot happen: OUT_DRAIN");
470 fatal("channel_still_open: bad channel type %d", c->type);
477 /* Returns the id of an open channel suitable for keepaliving */
480 channel_find_open(void)
485 for (i = 0; i < channels_alloc; i++) {
490 case SSH_CHANNEL_CLOSED:
491 case SSH_CHANNEL_DYNAMIC:
492 case SSH_CHANNEL_X11_LISTENER:
493 case SSH_CHANNEL_PORT_LISTENER:
494 case SSH_CHANNEL_RPORT_LISTENER:
495 case SSH_CHANNEL_OPENING:
496 case SSH_CHANNEL_CONNECTING:
497 case SSH_CHANNEL_ZOMBIE:
499 case SSH_CHANNEL_LARVAL:
500 case SSH_CHANNEL_AUTH_SOCKET:
501 case SSH_CHANNEL_OPEN:
502 case SSH_CHANNEL_X11_OPEN:
504 case SSH_CHANNEL_INPUT_DRAINING:
505 case SSH_CHANNEL_OUTPUT_DRAINING:
507 fatal("cannot happen: OUT_DRAIN");
510 fatal("channel_find_open: bad channel type %d", c->type);
519 * Returns a message describing the currently open forwarded connections,
520 * suitable for sending to the client. The message contains crlf pairs for
525 channel_open_message(void)
532 buffer_init(&buffer);
533 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
534 buffer_append(&buffer, buf, strlen(buf));
535 for (i = 0; i < channels_alloc; i++) {
540 case SSH_CHANNEL_X11_LISTENER:
541 case SSH_CHANNEL_PORT_LISTENER:
542 case SSH_CHANNEL_RPORT_LISTENER:
543 case SSH_CHANNEL_CLOSED:
544 case SSH_CHANNEL_AUTH_SOCKET:
545 case SSH_CHANNEL_ZOMBIE:
547 case SSH_CHANNEL_LARVAL:
548 case SSH_CHANNEL_OPENING:
549 case SSH_CHANNEL_CONNECTING:
550 case SSH_CHANNEL_DYNAMIC:
551 case SSH_CHANNEL_OPEN:
552 case SSH_CHANNEL_X11_OPEN:
553 case SSH_CHANNEL_INPUT_DRAINING:
554 case SSH_CHANNEL_OUTPUT_DRAINING:
555 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
556 c->self, c->remote_name,
557 c->type, c->remote_id,
558 c->istate, buffer_len(&c->input),
559 c->ostate, buffer_len(&c->output),
561 buffer_append(&buffer, buf, strlen(buf));
564 fatal("channel_open_message: bad channel type %d", c->type);
568 buffer_append(&buffer, "\0", 1);
569 cp = xstrdup(buffer_ptr(&buffer));
570 buffer_free(&buffer);
575 channel_send_open(int id)
577 Channel *c = channel_lookup(id);
579 log("channel_send_open: %d: bad id", id);
582 debug("send channel open %d", id);
583 packet_start(SSH2_MSG_CHANNEL_OPEN);
584 packet_put_cstring(c->ctype);
585 packet_put_int(c->self);
586 packet_put_int(c->local_window);
587 packet_put_int(c->local_maxpacket);
592 channel_request(int id, char *service, int wantconfirm)
594 channel_request_start(id, service, wantconfirm);
596 debug("channel request %d: %s", id, service) ;
599 channel_request_start(int id, char *service, int wantconfirm)
601 Channel *c = channel_lookup(id);
603 log("channel_request: %d: bad id", id);
606 packet_start(SSH2_MSG_CHANNEL_REQUEST);
607 packet_put_int(c->remote_id);
608 packet_put_cstring(service);
609 packet_put_char(wantconfirm);
612 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
614 Channel *c = channel_lookup(id);
616 log("channel_register_callback: %d: bad id", id);
624 channel_register_cleanup(int id, channel_callback_fn *fn)
626 Channel *c = channel_lookup(id);
628 log("channel_register_cleanup: %d: bad id", id);
634 channel_cancel_cleanup(int id)
636 Channel *c = channel_lookup(id);
638 log("channel_cancel_cleanup: %d: bad id", id);
641 c->detach_user = NULL;
644 channel_register_filter(int id, channel_filter_fn *fn)
646 Channel *c = channel_lookup(id);
648 log("channel_register_filter: %d: bad id", id);
651 c->input_filter = fn;
655 channel_set_fds(int id, int rfd, int wfd, int efd,
656 int extusage, int nonblock)
658 Channel *c = channel_lookup(id);
659 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
660 fatal("channel_activate for non-larval channel %d.", id);
661 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
662 c->type = SSH_CHANNEL_OPEN;
663 /* XXX window size? */
664 c->local_window = c->local_window_max = c->local_maxpacket * 2;
665 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
666 packet_put_int(c->remote_id);
667 packet_put_int(c->local_window);
672 * 'channel_pre*' are called just before select() to add any bits relevant to
673 * channels in the select bitmasks.
676 * 'channel_post*': perform any appropriate operations for channels which
677 * have events pending.
679 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
680 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
681 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
684 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
686 FD_SET(c->sock, readset);
690 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
692 debug3("channel %d: waiting for connection", c->self);
693 FD_SET(c->sock, writeset);
697 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
699 if (buffer_len(&c->input) < packet_get_maxsize())
700 FD_SET(c->sock, readset);
701 if (buffer_len(&c->output) > 0)
702 FD_SET(c->sock, writeset);
706 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
708 /* test whether sockets are 'alive' for read/write */
709 if (c->istate == CHAN_INPUT_OPEN)
710 if (buffer_len(&c->input) < packet_get_maxsize())
711 FD_SET(c->sock, readset);
712 if (c->ostate == CHAN_OUTPUT_OPEN ||
713 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
714 if (buffer_len(&c->output) > 0) {
715 FD_SET(c->sock, writeset);
716 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
723 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
725 if (c->istate == CHAN_INPUT_OPEN &&
726 c->remote_window > 0 &&
727 buffer_len(&c->input) < c->remote_window)
728 FD_SET(c->rfd, readset);
729 if (c->ostate == CHAN_OUTPUT_OPEN ||
730 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
731 if (buffer_len(&c->output) > 0) {
732 FD_SET(c->wfd, writeset);
733 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
737 /** XXX check close conditions, too */
739 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
740 buffer_len(&c->extended) > 0)
741 FD_SET(c->efd, writeset);
742 else if (c->extended_usage == CHAN_EXTENDED_READ &&
743 buffer_len(&c->extended) < c->remote_window)
744 FD_SET(c->efd, readset);
749 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
751 if (buffer_len(&c->input) == 0) {
752 packet_start(SSH_MSG_CHANNEL_CLOSE);
753 packet_put_int(c->remote_id);
755 c->type = SSH_CHANNEL_CLOSED;
756 debug("channel %d: closing after input drain.", c->self);
761 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
763 if (buffer_len(&c->output) == 0)
766 FD_SET(c->sock, writeset);
770 * This is a special state for X11 authentication spoofing. An opened X11
771 * connection (when authentication spoofing is being done) remains in this
772 * state until the first packet has been completely read. The authentication
773 * data in that packet is then substituted by the real data if it matches the
774 * fake data, and the channel is put into normal mode.
775 * XXX All this happens at the client side.
776 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
779 x11_open_helper(Buffer *b)
782 u_int proto_len, data_len;
784 /* Check if the fixed size part of the packet is in buffer. */
785 if (buffer_len(b) < 12)
788 /* Parse the lengths of variable-length fields. */
790 if (ucp[0] == 0x42) { /* Byte order MSB first. */
791 proto_len = 256 * ucp[6] + ucp[7];
792 data_len = 256 * ucp[8] + ucp[9];
793 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
794 proto_len = ucp[6] + 256 * ucp[7];
795 data_len = ucp[8] + 256 * ucp[9];
797 debug("Initial X11 packet contains bad byte order byte: 0x%x",
802 /* Check if the whole packet is in buffer. */
804 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
807 /* Check if authentication protocol matches. */
808 if (proto_len != strlen(x11_saved_proto) ||
809 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
810 debug("X11 connection uses different authentication protocol.");
813 /* Check if authentication data matches our fake data. */
814 if (data_len != x11_fake_data_len ||
815 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
816 x11_fake_data, x11_fake_data_len) != 0) {
817 debug("X11 auth data does not match fake data.");
820 /* Check fake data length */
821 if (x11_fake_data_len != x11_saved_data_len) {
822 error("X11 fake_data_len %d != saved_data_len %d",
823 x11_fake_data_len, x11_saved_data_len);
827 * Received authentication protocol and data match
828 * our fake data. Substitute the fake data with real
831 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
832 x11_saved_data, x11_saved_data_len);
837 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
839 int ret = x11_open_helper(&c->output);
841 /* Start normal processing for the channel. */
842 c->type = SSH_CHANNEL_OPEN;
843 channel_pre_open_13(c, readset, writeset);
844 } else if (ret == -1) {
846 * We have received an X11 connection that has bad
847 * authentication information.
849 log("X11 connection rejected because of wrong authentication.");
850 buffer_clear(&c->input);
851 buffer_clear(&c->output);
852 channel_close_fd(&c->sock);
854 c->type = SSH_CHANNEL_CLOSED;
855 packet_start(SSH_MSG_CHANNEL_CLOSE);
856 packet_put_int(c->remote_id);
862 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
864 int ret = x11_open_helper(&c->output);
866 /* c->force_drain = 1; */
869 c->type = SSH_CHANNEL_OPEN;
871 channel_pre_open_20(c, readset, writeset);
873 channel_pre_open_15(c, readset, writeset);
874 } else if (ret == -1) {
875 log("X11 connection rejected because of wrong authentication.");
876 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
878 buffer_clear(&c->input);
880 buffer_clear(&c->output);
881 /* for proto v1, the peer will send an IEOF */
883 chan_write_failed(c);
885 c->type = SSH_CHANNEL_OPEN;
886 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
890 /* try to decode a socks4 header */
892 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
895 int len, have, i, found;
901 struct in_addr dest_addr;
904 debug2("channel %d: decode socks4", c->self);
906 have = buffer_len(&c->input);
907 len = sizeof(s4_req);
910 p = buffer_ptr(&c->input);
911 for (found = 0, i = len; i < have; i++) {
917 /* the peer is probably sending garbage */
918 debug("channel %d: decode socks4: too long",
925 buffer_get(&c->input, (char *)&s4_req.version, 1);
926 buffer_get(&c->input, (char *)&s4_req.command, 1);
927 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
928 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
929 have = buffer_len(&c->input);
930 p = buffer_ptr(&c->input);
932 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
934 fatal("channel %d: decode socks4: len %d > have %d",
936 strlcpy(username, p, sizeof(username));
937 buffer_consume(&c->input, len);
938 buffer_consume(&c->input, 1); /* trailing '\0' */
940 host = inet_ntoa(s4_req.dest_addr);
941 strlcpy(c->path, host, sizeof(c->path));
942 c->host_port = ntohs(s4_req.dest_port);
944 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
945 c->self, host, c->host_port, s4_req.command);
947 if (s4_req.command != 1) {
948 debug("channel %d: cannot handle: socks4 cn %d",
949 c->self, s4_req.command);
952 s4_rsp.version = 0; /* vn: 0 for reply */
953 s4_rsp.command = 90; /* cd: req granted */
954 s4_rsp.dest_port = 0; /* ignored */
955 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
956 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
960 /* dynamic port forwarding */
962 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
967 have = buffer_len(&c->input);
969 debug2("channel %d: pre_dynamic: have %d", c->self, have);
970 /* buffer_dump(&c->input); */
971 /* check if the fixed size part of the packet is in buffer. */
974 FD_SET(c->sock, readset);
977 /* try to guess the protocol */
978 p = buffer_ptr(&c->input);
981 ret = channel_decode_socks4(c, readset, writeset);
989 } else if (ret == 0) {
990 debug2("channel %d: pre_dynamic: need more", c->self);
992 FD_SET(c->sock, readset);
994 /* switch to the next state */
995 c->type = SSH_CHANNEL_OPENING;
996 port_open_helper(c, "direct-tcpip");
1000 /* This is our fake X11 server socket. */
1002 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1005 struct sockaddr addr;
1006 int newsock, on = 1;
1008 char buf[16384], *remote_ipaddr;
1011 if (FD_ISSET(c->sock, readset)) {
1012 debug("X11 connection requested.");
1013 addrlen = sizeof(addr);
1014 newsock = accept(c->sock, &addr, &addrlen);
1015 if (c->single_connection) {
1016 debug("single_connection: closing X11 listener.");
1017 channel_close_fd(&c->sock);
1021 error("accept: %.100s", strerror(errno));
1024 if (setsockopt(newsock, IPPROTO_TCP, TCP_NODELAY, &on,
1026 error("setsockopt TCP_NODELAY: %.100s",
1028 remote_ipaddr = get_peer_ipaddr(newsock);
1029 remote_port = get_peer_port(newsock);
1030 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1031 remote_ipaddr, remote_port);
1033 nc = channel_new("accepted x11 socket",
1034 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1035 c->local_window_max, c->local_maxpacket,
1036 0, xstrdup(buf), 1);
1039 xfree(remote_ipaddr);
1043 packet_start(SSH2_MSG_CHANNEL_OPEN);
1044 packet_put_cstring("x11");
1045 packet_put_int(nc->self);
1046 packet_put_int(nc->local_window_max);
1047 packet_put_int(nc->local_maxpacket);
1048 /* originator ipaddr and port */
1049 packet_put_cstring(remote_ipaddr);
1050 if (datafellows & SSH_BUG_X11FWD) {
1051 debug("ssh2 x11 bug compat mode");
1053 packet_put_int(remote_port);
1057 packet_start(SSH_SMSG_X11_OPEN);
1058 packet_put_int(nc->self);
1059 if (packet_get_protocol_flags() &
1060 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1061 packet_put_cstring(buf);
1064 xfree(remote_ipaddr);
1069 port_open_helper(Channel *c, char *rtype)
1073 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1074 u_short remote_port = get_peer_port(c->sock);
1076 direct = (strcmp(rtype, "direct-tcpip") == 0);
1078 snprintf(buf, sizeof buf,
1079 "%s: listening port %d for %.100s port %d, "
1080 "connect from %.200s port %d",
1081 rtype, c->listening_port, c->path, c->host_port,
1082 remote_ipaddr, remote_port);
1084 xfree(c->remote_name);
1085 c->remote_name = xstrdup(buf);
1088 packet_start(SSH2_MSG_CHANNEL_OPEN);
1089 packet_put_cstring(rtype);
1090 packet_put_int(c->self);
1091 packet_put_int(c->local_window_max);
1092 packet_put_int(c->local_maxpacket);
1094 /* target host, port */
1095 packet_put_cstring(c->path);
1096 packet_put_int(c->host_port);
1098 /* listen address, port */
1099 packet_put_cstring(c->path);
1100 packet_put_int(c->listening_port);
1102 /* originator host and port */
1103 packet_put_cstring(remote_ipaddr);
1104 packet_put_int(remote_port);
1107 packet_start(SSH_MSG_PORT_OPEN);
1108 packet_put_int(c->self);
1109 packet_put_cstring(c->path);
1110 packet_put_int(c->host_port);
1111 if (packet_get_protocol_flags() &
1112 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1113 packet_put_cstring(c->remote_name);
1116 xfree(remote_ipaddr);
1120 * This socket is listening for connections to a forwarded TCP/IP port.
1123 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1126 struct sockaddr addr;
1127 int newsock, nextstate;
1131 if (FD_ISSET(c->sock, readset)) {
1132 debug("Connection to port %d forwarding "
1133 "to %.100s port %d requested.",
1134 c->listening_port, c->path, c->host_port);
1136 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1137 nextstate = SSH_CHANNEL_OPENING;
1138 rtype = "forwarded-tcpip";
1140 if (c->host_port == 0) {
1141 nextstate = SSH_CHANNEL_DYNAMIC;
1142 rtype = "dynamic-tcpip";
1144 nextstate = SSH_CHANNEL_OPENING;
1145 rtype = "direct-tcpip";
1149 addrlen = sizeof(addr);
1150 newsock = accept(c->sock, &addr, &addrlen);
1152 error("accept: %.100s", strerror(errno));
1155 nc = channel_new(rtype,
1156 nextstate, newsock, newsock, -1,
1157 c->local_window_max, c->local_maxpacket,
1158 0, xstrdup(rtype), 1);
1160 error("channel_post_port_listener: no new channel:");
1164 nc->listening_port = c->listening_port;
1165 nc->host_port = c->host_port;
1166 strlcpy(nc->path, c->path, sizeof(nc->path));
1168 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1170 * do not call the channel_post handler until
1171 * this flag has been reset by a pre-handler.
1172 * otherwise the FD_ISSET calls might overflow
1176 port_open_helper(nc, rtype);
1182 * This is the authentication agent socket listening for connections from
1186 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1191 struct sockaddr addr;
1194 if (FD_ISSET(c->sock, readset)) {
1195 addrlen = sizeof(addr);
1196 newsock = accept(c->sock, &addr, &addrlen);
1198 error("accept from auth socket: %.100s", strerror(errno));
1201 name = xstrdup("accepted auth socket");
1202 nc = channel_new("accepted auth socket",
1203 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1204 c->local_window_max, c->local_maxpacket,
1207 error("channel_post_auth_listener: channel_new failed");
1212 packet_start(SSH2_MSG_CHANNEL_OPEN);
1213 packet_put_cstring("auth-agent@openssh.com");
1214 packet_put_int(nc->self);
1215 packet_put_int(c->local_window_max);
1216 packet_put_int(c->local_maxpacket);
1218 packet_start(SSH_SMSG_AGENT_OPEN);
1219 packet_put_int(nc->self);
1226 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1229 socklen_t sz = sizeof(err);
1231 if (FD_ISSET(c->sock, writeset)) {
1232 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1235 error("getsockopt SO_ERROR failed");
1238 debug("channel %d: connected", c->self);
1239 c->type = SSH_CHANNEL_OPEN;
1241 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1242 packet_put_int(c->remote_id);
1243 packet_put_int(c->self);
1244 packet_put_int(c->local_window);
1245 packet_put_int(c->local_maxpacket);
1247 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1248 packet_put_int(c->remote_id);
1249 packet_put_int(c->self);
1252 debug("channel %d: not connected: %s",
1253 c->self, strerror(err));
1255 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1256 packet_put_int(c->remote_id);
1257 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1258 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1259 packet_put_cstring(strerror(err));
1260 packet_put_cstring("");
1263 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1264 packet_put_int(c->remote_id);
1273 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1279 FD_ISSET(c->rfd, readset)) {
1280 len = read(c->rfd, buf, sizeof(buf));
1281 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1284 debug("channel %d: read<=0 rfd %d len %d",
1285 c->self, c->rfd, len);
1286 if (c->type != SSH_CHANNEL_OPEN) {
1287 debug("channel %d: not open", c->self);
1290 } else if (compat13) {
1291 buffer_consume(&c->output, buffer_len(&c->output));
1292 c->type = SSH_CHANNEL_INPUT_DRAINING;
1293 debug("channel %d: input draining.", c->self);
1295 chan_read_failed(c);
1299 if (c->input_filter != NULL) {
1300 if (c->input_filter(c, buf, len) == -1) {
1301 debug("channel %d: filter stops", c->self);
1302 chan_read_failed(c);
1305 buffer_append(&c->input, buf, len);
1311 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1318 /* Send buffered output data to the socket. */
1320 FD_ISSET(c->wfd, writeset) &&
1321 buffer_len(&c->output) > 0) {
1322 data = buffer_ptr(&c->output);
1323 dlen = buffer_len(&c->output);
1324 len = write(c->wfd, data, dlen);
1325 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1328 if (c->type != SSH_CHANNEL_OPEN) {
1329 debug("channel %d: not open", c->self);
1332 } else if (compat13) {
1333 buffer_consume(&c->output, buffer_len(&c->output));
1334 debug("channel %d: input draining.", c->self);
1335 c->type = SSH_CHANNEL_INPUT_DRAINING;
1337 chan_write_failed(c);
1341 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1342 if (tcgetattr(c->wfd, &tio) == 0 &&
1343 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1345 * Simulate echo to reduce the impact of
1346 * traffic analysis. We need to match the
1347 * size of a SSH2_MSG_CHANNEL_DATA message
1348 * (4 byte channel id + data)
1350 packet_send_ignore(4 + len);
1354 buffer_consume(&c->output, len);
1355 if (compat20 && len > 0) {
1356 c->local_consumed += len;
1362 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1367 /** XXX handle drain efd, too */
1369 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1370 FD_ISSET(c->efd, writeset) &&
1371 buffer_len(&c->extended) > 0) {
1372 len = write(c->efd, buffer_ptr(&c->extended),
1373 buffer_len(&c->extended));
1374 debug2("channel %d: written %d to efd %d",
1375 c->self, len, c->efd);
1376 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1379 debug2("channel %d: closing write-efd %d",
1381 channel_close_fd(&c->efd);
1383 buffer_consume(&c->extended, len);
1384 c->local_consumed += len;
1386 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1387 FD_ISSET(c->efd, readset)) {
1388 len = read(c->efd, buf, sizeof(buf));
1389 debug2("channel %d: read %d from efd %d",
1390 c->self, len, c->efd);
1391 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1394 debug2("channel %d: closing read-efd %d",
1396 channel_close_fd(&c->efd);
1398 buffer_append(&c->extended, buf, len);
1405 channel_check_window(Channel *c)
1407 if (c->type == SSH_CHANNEL_OPEN &&
1408 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1409 c->local_window < c->local_window_max/2 &&
1410 c->local_consumed > 0) {
1411 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1412 packet_put_int(c->remote_id);
1413 packet_put_int(c->local_consumed);
1415 debug2("channel %d: window %d sent adjust %d",
1416 c->self, c->local_window,
1418 c->local_window += c->local_consumed;
1419 c->local_consumed = 0;
1425 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1429 channel_handle_rfd(c, readset, writeset);
1430 channel_handle_wfd(c, readset, writeset);
1434 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1438 channel_handle_rfd(c, readset, writeset);
1439 channel_handle_wfd(c, readset, writeset);
1440 channel_handle_efd(c, readset, writeset);
1442 channel_check_window(c);
1446 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1449 /* Send buffered output data to the socket. */
1450 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1451 len = write(c->sock, buffer_ptr(&c->output),
1452 buffer_len(&c->output));
1454 buffer_consume(&c->output, buffer_len(&c->output));
1456 buffer_consume(&c->output, len);
1461 channel_handler_init_20(void)
1463 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1464 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1465 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1466 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1467 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1468 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1469 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1470 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1472 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1473 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1474 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1475 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1476 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1477 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1478 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1482 channel_handler_init_13(void)
1484 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1485 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1486 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1487 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1488 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1489 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1490 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1491 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1492 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1494 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1495 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1496 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1497 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1498 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1499 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1500 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1504 channel_handler_init_15(void)
1506 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1507 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1508 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1509 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1510 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1511 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1512 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1514 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1515 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1516 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1517 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1518 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1519 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1523 channel_handler_init(void)
1526 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1527 channel_pre[i] = NULL;
1528 channel_post[i] = NULL;
1531 channel_handler_init_20();
1533 channel_handler_init_13();
1535 channel_handler_init_15();
1538 /* gc dead channels */
1540 channel_garbage_collect(Channel *c)
1544 if (c->detach_user != NULL) {
1545 if (!chan_is_dead(c, 0))
1547 debug("channel %d: gc: notify user", c->self);
1548 c->detach_user(c->self, NULL);
1549 /* if we still have a callback */
1550 if (c->detach_user != NULL)
1552 debug("channel %d: gc: user detached", c->self);
1554 if (!chan_is_dead(c, 1))
1556 debug("channel %d: garbage collecting", c->self);
1561 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1563 static int did_init = 0;
1568 channel_handler_init();
1571 for (i = 0; i < channels_alloc; i++) {
1575 if (ftab[c->type] != NULL)
1576 (*ftab[c->type])(c, readset, writeset);
1577 channel_garbage_collect(c);
1582 * Allocate/update select bitmasks and add any bits relevant to channels in
1586 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1587 int *nallocp, int rekeying)
1592 n = MAX(*maxfdp, channel_max_fd);
1594 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1595 /* perhaps check sz < nalloc/2 and shrink? */
1596 if (*readsetp == NULL || sz > *nallocp) {
1597 *readsetp = xrealloc(*readsetp, sz);
1598 *writesetp = xrealloc(*writesetp, sz);
1602 memset(*readsetp, 0, sz);
1603 memset(*writesetp, 0, sz);
1606 channel_handler(channel_pre, *readsetp, *writesetp);
1610 * After select, perform any appropriate operations for channels which have
1614 channel_after_select(fd_set * readset, fd_set * writeset)
1616 channel_handler(channel_post, readset, writeset);
1620 /* If there is data to send to the connection, enqueue some of it now. */
1623 channel_output_poll(void)
1628 for (i = 0; i < channels_alloc; i++) {
1634 * We are only interested in channels that can have buffered
1638 if (c->type != SSH_CHANNEL_OPEN &&
1639 c->type != SSH_CHANNEL_INPUT_DRAINING)
1642 if (c->type != SSH_CHANNEL_OPEN)
1646 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1647 /* XXX is this true? */
1648 debug3("channel %d: will not send data after close", c->self);
1652 /* Get the amount of buffered data for this channel. */
1653 if ((c->istate == CHAN_INPUT_OPEN ||
1654 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1655 (len = buffer_len(&c->input)) > 0) {
1657 * Send some data for the other side over the secure
1661 if (len > c->remote_window)
1662 len = c->remote_window;
1663 if (len > c->remote_maxpacket)
1664 len = c->remote_maxpacket;
1666 if (packet_is_interactive()) {
1670 /* Keep the packets at reasonable size. */
1671 if (len > packet_get_maxsize()/2)
1672 len = packet_get_maxsize()/2;
1676 packet_start(compat20 ?
1677 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1678 packet_put_int(c->remote_id);
1679 packet_put_string(buffer_ptr(&c->input), len);
1681 buffer_consume(&c->input, len);
1682 c->remote_window -= len;
1684 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1686 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1688 * input-buffer is empty and read-socket shutdown:
1689 * tell peer, that we will not send more data: send IEOF
1693 /* Send extended data, i.e. stderr */
1695 c->remote_window > 0 &&
1696 (len = buffer_len(&c->extended)) > 0 &&
1697 c->extended_usage == CHAN_EXTENDED_READ) {
1698 debug2("channel %d: rwin %d elen %d euse %d",
1699 c->self, c->remote_window, buffer_len(&c->extended),
1701 if (len > c->remote_window)
1702 len = c->remote_window;
1703 if (len > c->remote_maxpacket)
1704 len = c->remote_maxpacket;
1705 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1706 packet_put_int(c->remote_id);
1707 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1708 packet_put_string(buffer_ptr(&c->extended), len);
1710 buffer_consume(&c->extended, len);
1711 c->remote_window -= len;
1712 debug2("channel %d: sent ext data %d", c->self, len);
1718 /* -- protocol input */
1721 channel_input_data(int type, u_int32_t seq, void *ctxt)
1728 /* Get the channel number and verify it. */
1729 id = packet_get_int();
1730 c = channel_lookup(id);
1732 packet_disconnect("Received data for nonexistent channel %d.", id);
1734 /* Ignore any data for non-open channels (might happen on close) */
1735 if (c->type != SSH_CHANNEL_OPEN &&
1736 c->type != SSH_CHANNEL_X11_OPEN)
1739 /* same for protocol 1.5 if output end is no longer open */
1740 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1744 data = packet_get_string(&data_len);
1747 if (data_len > c->local_maxpacket) {
1748 log("channel %d: rcvd big packet %d, maxpack %d",
1749 c->self, data_len, c->local_maxpacket);
1751 if (data_len > c->local_window) {
1752 log("channel %d: rcvd too much data %d, win %d",
1753 c->self, data_len, c->local_window);
1757 c->local_window -= data_len;
1760 buffer_append(&c->output, data, data_len);
1765 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1773 /* Get the channel number and verify it. */
1774 id = packet_get_int();
1775 c = channel_lookup(id);
1778 packet_disconnect("Received extended_data for bad channel %d.", id);
1779 if (c->type != SSH_CHANNEL_OPEN) {
1780 log("channel %d: ext data for non open", id);
1783 tcode = packet_get_int();
1785 c->extended_usage != CHAN_EXTENDED_WRITE ||
1786 tcode != SSH2_EXTENDED_DATA_STDERR) {
1787 log("channel %d: bad ext data", c->self);
1790 data = packet_get_string(&data_len);
1792 if (data_len > c->local_window) {
1793 log("channel %d: rcvd too much extended_data %d, win %d",
1794 c->self, data_len, c->local_window);
1798 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1799 c->local_window -= data_len;
1800 buffer_append(&c->extended, data, data_len);
1805 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1810 id = packet_get_int();
1812 c = channel_lookup(id);
1814 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1817 /* XXX force input close */
1818 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1819 debug("channel %d: FORCE input drain", c->self);
1820 c->istate = CHAN_INPUT_WAIT_DRAIN;
1826 channel_input_close(int type, u_int32_t seq, void *ctxt)
1831 id = packet_get_int();
1833 c = channel_lookup(id);
1835 packet_disconnect("Received close for nonexistent channel %d.", id);
1838 * Send a confirmation that we have closed the channel and no more
1839 * data is coming for it.
1841 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1842 packet_put_int(c->remote_id);
1846 * If the channel is in closed state, we have sent a close request,
1847 * and the other side will eventually respond with a confirmation.
1848 * Thus, we cannot free the channel here, because then there would be
1849 * no-one to receive the confirmation. The channel gets freed when
1850 * the confirmation arrives.
1852 if (c->type != SSH_CHANNEL_CLOSED) {
1854 * Not a closed channel - mark it as draining, which will
1855 * cause it to be freed later.
1857 buffer_consume(&c->input, buffer_len(&c->input));
1858 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1862 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1864 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
1866 int id = packet_get_int();
1867 Channel *c = channel_lookup(id);
1871 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1872 chan_rcvd_oclose(c);
1876 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
1878 int id = packet_get_int();
1879 Channel *c = channel_lookup(id);
1883 packet_disconnect("Received close confirmation for "
1884 "out-of-range channel %d.", id);
1885 if (c->type != SSH_CHANNEL_CLOSED)
1886 packet_disconnect("Received close confirmation for "
1887 "non-closed channel %d (type %d).", id, c->type);
1892 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
1897 id = packet_get_int();
1898 c = channel_lookup(id);
1900 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1901 packet_disconnect("Received open confirmation for "
1902 "non-opening channel %d.", id);
1903 remote_id = packet_get_int();
1904 /* Record the remote channel number and mark that the channel is now open. */
1905 c->remote_id = remote_id;
1906 c->type = SSH_CHANNEL_OPEN;
1909 c->remote_window = packet_get_int();
1910 c->remote_maxpacket = packet_get_int();
1911 if (c->cb_fn != NULL && c->cb_event == type) {
1912 debug2("callback start");
1913 c->cb_fn(c->self, c->cb_arg);
1914 debug2("callback done");
1916 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1917 c->remote_window, c->remote_maxpacket);
1923 reason2txt(int reason)
1926 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1927 return "administratively prohibited";
1928 case SSH2_OPEN_CONNECT_FAILED:
1929 return "connect failed";
1930 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1931 return "unknown channel type";
1932 case SSH2_OPEN_RESOURCE_SHORTAGE:
1933 return "resource shortage";
1935 return "unknown reason";
1939 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
1942 char *msg = NULL, *lang = NULL;
1945 id = packet_get_int();
1946 c = channel_lookup(id);
1948 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1949 packet_disconnect("Received open failure for "
1950 "non-opening channel %d.", id);
1952 reason = packet_get_int();
1953 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1954 msg = packet_get_string(NULL);
1955 lang = packet_get_string(NULL);
1957 log("channel %d: open failed: %s%s%s", id,
1958 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1965 /* Free the channel. This will also close the socket. */
1970 channel_input_channel_request(int type, u_int32_t seq, void *ctxt)
1975 id = packet_get_int();
1976 c = channel_lookup(id);
1979 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1980 packet_disconnect("Received request for "
1981 "non-open channel %d.", id);
1982 if (c->cb_fn != NULL && c->cb_event == type) {
1983 debug2("callback start");
1984 c->cb_fn(c->self, c->cb_arg);
1985 debug2("callback done");
1987 char *service = packet_get_string(NULL);
1988 debug("channel %d: rcvd request for %s", c->self, service);
1989 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1995 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2003 /* Get the channel number and verify it. */
2004 id = packet_get_int();
2005 c = channel_lookup(id);
2007 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2008 log("Received window adjust for "
2009 "non-open channel %d.", id);
2012 adjust = packet_get_int();
2014 debug2("channel %d: rcvd adjust %d", id, adjust);
2015 c->remote_window += adjust;
2019 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2023 char *host, *originator_string;
2024 int remote_id, sock = -1;
2026 remote_id = packet_get_int();
2027 host = packet_get_string(NULL);
2028 host_port = packet_get_int();
2030 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2031 originator_string = packet_get_string(NULL);
2033 originator_string = xstrdup("unknown (remote did not supply name)");
2036 sock = channel_connect_to(host, host_port);
2038 c = channel_new("connected socket",
2039 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2040 originator_string, 1);
2042 error("channel_input_port_open: channel_new failed");
2045 c->remote_id = remote_id;
2049 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2050 packet_put_int(remote_id);
2057 /* -- tcp forwarding */
2060 channel_set_af(int af)
2066 * Initiate forwarding of connections to local port "port" through the secure
2067 * channel to host:port from remote side.
2070 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2071 u_short port_to_connect, int gateway_ports)
2073 return channel_request_forwarding(
2075 host_to_connect, port_to_connect,
2076 gateway_ports, /*remote_fwd*/ 0);
2080 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2081 * (SSH_CHANNEL_RPORT_LISTENER).
2084 channel_request_forwarding(
2085 const char *listen_address, u_short listen_port,
2086 const char *host_to_connect, u_short port_to_connect,
2087 int gateway_ports, int remote_fwd)
2090 int success, sock, on = 1, type;
2091 struct addrinfo hints, *ai, *aitop;
2092 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2094 struct linger linger;
2099 host = listen_address;
2100 type = SSH_CHANNEL_RPORT_LISTENER;
2102 host = host_to_connect;
2103 type = SSH_CHANNEL_PORT_LISTENER;
2106 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2107 error("Forward host name too long.");
2111 /* XXX listen_address is currently ignored */
2113 * getaddrinfo returns a loopback address if the hostname is
2114 * set to NULL and hints.ai_flags is not AI_PASSIVE
2116 memset(&hints, 0, sizeof(hints));
2117 hints.ai_family = IPv4or6;
2118 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2119 hints.ai_socktype = SOCK_STREAM;
2120 snprintf(strport, sizeof strport, "%d", listen_port);
2121 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2122 packet_disconnect("getaddrinfo: fatal error");
2124 for (ai = aitop; ai; ai = ai->ai_next) {
2125 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2127 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2128 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2129 error("channel_request_forwarding: getnameinfo failed");
2132 /* Create a port to listen for the host. */
2133 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2135 /* this is no error since kernel may not support ipv6 */
2136 verbose("socket: %.100s", strerror(errno));
2140 * Set socket options. We would like the socket to disappear
2141 * as soon as it has been closed for whatever reason.
2143 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2145 linger.l_linger = 5;
2146 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2147 debug("Local forwarding listening on %s port %s.", ntop, strport);
2149 /* Bind the socket to the address. */
2150 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2151 /* address can be in use ipv6 address is already bound */
2153 error("bind: %.100s", strerror(errno));
2155 verbose("bind: %.100s", strerror(errno));
2160 /* Start listening for connections on the socket. */
2161 if (listen(sock, 5) < 0) {
2162 error("listen: %.100s", strerror(errno));
2166 /* Allocate a channel number for the socket. */
2167 c = channel_new("port listener", type, sock, sock, -1,
2168 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2169 0, xstrdup("port listener"), 1);
2171 error("channel_request_forwarding: channel_new failed");
2175 strlcpy(c->path, host, sizeof(c->path));
2176 c->host_port = port_to_connect;
2177 c->listening_port = listen_port;
2181 error("channel_request_forwarding: cannot listen to port: %d",
2183 freeaddrinfo(aitop);
2188 * Initiate forwarding of connections to port "port" on remote host through
2189 * the secure channel to host:port from local side.
2193 channel_request_remote_forwarding(u_short listen_port,
2194 const char *host_to_connect, u_short port_to_connect)
2196 int type, success = 0;
2198 /* Record locally that connection to this host/port is permitted. */
2199 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2200 fatal("channel_request_remote_forwarding: too many forwards");
2202 /* Send the forward request to the remote side. */
2204 const char *address_to_bind = "0.0.0.0";
2205 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2206 packet_put_cstring("tcpip-forward");
2207 packet_put_char(0); /* boolean: want reply */
2208 packet_put_cstring(address_to_bind);
2209 packet_put_int(listen_port);
2211 packet_write_wait();
2212 /* Assume that server accepts the request */
2215 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2216 packet_put_int(listen_port);
2217 packet_put_cstring(host_to_connect);
2218 packet_put_int(port_to_connect);
2220 packet_write_wait();
2222 /* Wait for response from the remote side. */
2223 type = packet_read();
2225 case SSH_SMSG_SUCCESS:
2228 case SSH_SMSG_FAILURE:
2229 log("Warning: Server denied remote port forwarding.");
2232 /* Unknown packet */
2233 packet_disconnect("Protocol error for port forward request:"
2234 "received packet type %d.", type);
2238 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2239 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2240 permitted_opens[num_permitted_opens].listen_port = listen_port;
2241 num_permitted_opens++;
2246 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2247 * listening for the port, and sends back a success reply (or disconnect
2248 * message if there was an error). This never returns if there was an error.
2252 channel_input_port_forward_request(int is_root, int gateway_ports)
2254 u_short port, host_port;
2257 /* Get arguments from the packet. */
2258 port = packet_get_int();
2259 hostname = packet_get_string(NULL);
2260 host_port = packet_get_int();
2264 * Check that an unprivileged user is not trying to forward a
2267 if (port < IPPORT_RESERVED && !is_root)
2268 packet_disconnect("Requested forwarding of port %d but user is not root.",
2271 /* Initiate forwarding */
2272 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2274 /* Free the argument string. */
2279 * Permits opening to any host/port if permitted_opens[] is empty. This is
2280 * usually called by the server, because the user could connect to any port
2281 * anyway, and the server has no way to know but to trust the client anyway.
2284 channel_permit_all_opens(void)
2286 if (num_permitted_opens == 0)
2287 all_opens_permitted = 1;
2291 channel_add_permitted_opens(char *host, int port)
2293 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2294 fatal("channel_request_remote_forwarding: too many forwards");
2295 debug("allow port forwarding to host %s port %d", host, port);
2297 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2298 permitted_opens[num_permitted_opens].port_to_connect = port;
2299 num_permitted_opens++;
2301 all_opens_permitted = 0;
2305 channel_clear_permitted_opens(void)
2309 for (i = 0; i < num_permitted_opens; i++)
2310 xfree(permitted_opens[i].host_to_connect);
2311 num_permitted_opens = 0;
2316 /* return socket to remote host, port */
2318 connect_to(const char *host, u_short port)
2320 struct addrinfo hints, *ai, *aitop;
2321 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2325 memset(&hints, 0, sizeof(hints));
2326 hints.ai_family = IPv4or6;
2327 hints.ai_socktype = SOCK_STREAM;
2328 snprintf(strport, sizeof strport, "%d", port);
2329 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2330 error("connect_to %.100s: unknown host (%s)", host,
2331 gai_strerror(gaierr));
2334 for (ai = aitop; ai; ai = ai->ai_next) {
2335 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2337 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2338 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2339 error("connect_to: getnameinfo failed");
2342 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2344 error("socket: %.100s", strerror(errno));
2347 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2348 fatal("connect_to: F_SETFL: %s", strerror(errno));
2349 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2350 errno != EINPROGRESS) {
2351 error("connect_to %.100s port %s: %.100s", ntop, strport,
2354 continue; /* fail -- try next */
2356 break; /* success */
2359 freeaddrinfo(aitop);
2361 error("connect_to %.100s port %d: failed.", host, port);
2369 channel_connect_by_listen_address(u_short listen_port)
2373 for (i = 0; i < num_permitted_opens; i++)
2374 if (permitted_opens[i].listen_port == listen_port)
2376 permitted_opens[i].host_to_connect,
2377 permitted_opens[i].port_to_connect);
2378 error("WARNING: Server requests forwarding for unknown listen_port %d",
2383 /* Check if connecting to that port is permitted and connect. */
2385 channel_connect_to(const char *host, u_short port)
2389 permit = all_opens_permitted;
2391 for (i = 0; i < num_permitted_opens; i++)
2392 if (permitted_opens[i].port_to_connect == port &&
2393 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2398 log("Received request to connect to host %.100s port %d, "
2399 "but the request was denied.", host, port);
2402 return connect_to(host, port);
2405 /* -- X11 forwarding */
2408 * Creates an internet domain socket for listening for X11 connections.
2409 * Returns a suitable display number for the DISPLAY variable, or -1 if
2413 x11_create_display_inet(int x11_display_offset, int gateway_ports,
2414 int single_connection)
2417 int display_number, sock;
2419 struct addrinfo hints, *ai, *aitop;
2420 char strport[NI_MAXSERV];
2421 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2423 for (display_number = x11_display_offset;
2424 display_number < MAX_DISPLAYS;
2426 port = 6000 + display_number;
2427 memset(&hints, 0, sizeof(hints));
2428 hints.ai_family = IPv4or6;
2429 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2430 hints.ai_socktype = SOCK_STREAM;
2431 snprintf(strport, sizeof strport, "%d", port);
2432 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2433 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2436 for (ai = aitop; ai; ai = ai->ai_next) {
2437 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2439 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2441 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2442 error("socket: %.100s", strerror(errno));
2445 debug("x11_create_display_inet: Socket family %d not supported",
2450 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2451 debug("bind port %d: %.100s", port, strerror(errno));
2457 for (n = 0; n < num_socks; n++) {
2463 socks[num_socks++] = sock;
2464 #ifndef DONT_TRY_OTHER_AF
2465 if (num_socks == NUM_SOCKS)
2471 freeaddrinfo(aitop);
2475 if (display_number >= MAX_DISPLAYS) {
2476 error("Failed to allocate internet-domain X11 display socket.");
2479 /* Start listening for connections on the socket. */
2480 for (n = 0; n < num_socks; n++) {
2482 if (listen(sock, 5) < 0) {
2483 error("listen: %.100s", strerror(errno));
2489 /* Allocate a channel for each socket. */
2490 for (n = 0; n < num_socks; n++) {
2492 nc = channel_new("x11 listener",
2493 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2494 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2495 0, xstrdup("X11 inet listener"), 1);
2497 nc->single_connection = single_connection;
2500 /* Return the display number for the DISPLAY environment variable. */
2501 return display_number;
2505 connect_local_xsocket(u_int dnr)
2508 struct sockaddr_un addr;
2510 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2512 error("socket: %.100s", strerror(errno));
2513 memset(&addr, 0, sizeof(addr));
2514 addr.sun_family = AF_UNIX;
2515 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2516 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2519 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2524 x11_connect_display(void)
2526 int display_number, sock = 0, on = 1;
2527 const char *display;
2528 char buf[1024], *cp;
2529 struct addrinfo hints, *ai, *aitop;
2530 char strport[NI_MAXSERV];
2533 /* Try to open a socket for the local X server. */
2534 display = getenv("DISPLAY");
2536 error("DISPLAY not set.");
2540 * Now we decode the value of the DISPLAY variable and make a
2541 * connection to the real X server.
2545 * Check if it is a unix domain socket. Unix domain displays are in
2546 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2548 if (strncmp(display, "unix:", 5) == 0 ||
2549 display[0] == ':') {
2550 /* Connect to the unix domain socket. */
2551 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2552 error("Could not parse display number from DISPLAY: %.100s",
2556 /* Create a socket. */
2557 sock = connect_local_xsocket(display_number);
2561 /* OK, we now have a connection to the display. */
2565 * Connect to an inet socket. The DISPLAY value is supposedly
2566 * hostname:d[.s], where hostname may also be numeric IP address.
2568 strlcpy(buf, display, sizeof(buf));
2569 cp = strchr(buf, ':');
2571 error("Could not find ':' in DISPLAY: %.100s", display);
2575 /* buf now contains the host name. But first we parse the display number. */
2576 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2577 error("Could not parse display number from DISPLAY: %.100s",
2582 /* Look up the host address */
2583 memset(&hints, 0, sizeof(hints));
2584 hints.ai_family = IPv4or6;
2585 hints.ai_socktype = SOCK_STREAM;
2586 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2587 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2588 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2591 for (ai = aitop; ai; ai = ai->ai_next) {
2592 /* Create a socket. */
2593 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2595 debug("socket: %.100s", strerror(errno));
2598 /* Connect it to the display. */
2599 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2600 debug("connect %.100s port %d: %.100s", buf,
2601 6000 + display_number, strerror(errno));
2608 freeaddrinfo(aitop);
2610 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2614 if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on) == -1)
2615 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
2620 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2621 * the remote channel number. We should do whatever we want, and respond
2622 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2626 x11_input_open(int type, u_int32_t seq, void *ctxt)
2629 int remote_id, sock = 0;
2632 debug("Received X11 open request.");
2634 remote_id = packet_get_int();
2636 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2637 remote_host = packet_get_string(NULL);
2639 remote_host = xstrdup("unknown (remote did not supply name)");
2643 /* Obtain a connection to the real X display. */
2644 sock = x11_connect_display();
2646 /* Allocate a channel for this connection. */
2647 c = channel_new("connected x11 socket",
2648 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2651 error("x11_input_open: channel_new failed");
2654 c->remote_id = remote_id;
2659 /* Send refusal to the remote host. */
2660 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2661 packet_put_int(remote_id);
2663 /* Send a confirmation to the remote host. */
2664 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2665 packet_put_int(remote_id);
2666 packet_put_int(c->self);
2671 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2673 deny_input_open(int type, u_int32_t seq, void *ctxt)
2675 int rchan = packet_get_int();
2677 case SSH_SMSG_AGENT_OPEN:
2678 error("Warning: ssh server tried agent forwarding.");
2680 case SSH_SMSG_X11_OPEN:
2681 error("Warning: ssh server tried X11 forwarding.");
2684 error("deny_input_open: type %d", type);
2687 error("Warning: this is probably a break in attempt by a malicious server.");
2688 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2689 packet_put_int(rchan);
2694 * Requests forwarding of X11 connections, generates fake authentication
2695 * data, and enables authentication spoofing.
2696 * This should be called in the client only.
2699 x11_request_forwarding_with_spoofing(int client_session_id,
2700 const char *proto, const char *data)
2702 u_int data_len = (u_int) strlen(data) / 2;
2703 u_int i, value, len;
2709 cp = getenv("DISPLAY");
2711 cp = strchr(cp, ':');
2713 cp = strchr(cp, '.');
2715 screen_number = atoi(cp + 1);
2719 /* Save protocol name. */
2720 x11_saved_proto = xstrdup(proto);
2723 * Extract real authentication data and generate fake data of the
2726 x11_saved_data = xmalloc(data_len);
2727 x11_fake_data = xmalloc(data_len);
2728 for (i = 0; i < data_len; i++) {
2729 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2730 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2732 rand = arc4random();
2733 x11_saved_data[i] = value;
2734 x11_fake_data[i] = rand & 0xff;
2737 x11_saved_data_len = data_len;
2738 x11_fake_data_len = data_len;
2740 /* Convert the fake data into hex. */
2741 len = 2 * data_len + 1;
2742 new_data = xmalloc(len);
2743 for (i = 0; i < data_len; i++)
2744 snprintf(new_data + 2 * i, len - 2 * i,
2745 "%02x", (u_char) x11_fake_data[i]);
2747 /* Send the request packet. */
2749 channel_request_start(client_session_id, "x11-req", 0);
2750 packet_put_char(0); /* XXX bool single connection */
2752 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2754 packet_put_cstring(proto);
2755 packet_put_cstring(new_data);
2756 packet_put_int(screen_number);
2758 packet_write_wait();
2763 /* -- agent forwarding */
2765 /* Sends a message to the server to request authentication fd forwarding. */
2768 auth_request_forwarding(void)
2770 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2772 packet_write_wait();
2776 * Returns the name of the forwarded authentication socket. Returns NULL if
2777 * there is no forwarded authentication socket. The returned value points to
2782 auth_get_socket_name(void)
2784 return auth_sock_name;
2787 /* removes the agent forwarding socket */
2790 auth_sock_cleanup_proc(void *_pw)
2792 struct passwd *pw = _pw;
2794 if (auth_sock_name) {
2795 temporarily_use_uid(pw);
2796 unlink(auth_sock_name);
2797 rmdir(auth_sock_dir);
2798 auth_sock_name = NULL;
2804 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2805 * This starts forwarding authentication requests.
2809 auth_input_request_forwarding(struct passwd * pw)
2813 struct sockaddr_un sunaddr;
2815 if (auth_get_socket_name() != NULL) {
2816 error("authentication forwarding requested twice.");
2820 /* Temporarily drop privileged uid for mkdir/bind. */
2821 temporarily_use_uid(pw);
2823 /* Allocate a buffer for the socket name, and format the name. */
2824 auth_sock_name = xmalloc(MAXPATHLEN);
2825 auth_sock_dir = xmalloc(MAXPATHLEN);
2826 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2828 /* Create private directory for socket */
2829 if (mkdtemp(auth_sock_dir) == NULL) {
2830 packet_send_debug("Agent forwarding disabled: "
2831 "mkdtemp() failed: %.100s", strerror(errno));
2833 xfree(auth_sock_name);
2834 xfree(auth_sock_dir);
2835 auth_sock_name = NULL;
2836 auth_sock_dir = NULL;
2839 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2840 auth_sock_dir, (int) getpid());
2842 /* delete agent socket on fatal() */
2843 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2845 /* Create the socket. */
2846 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2848 packet_disconnect("socket: %.100s", strerror(errno));
2850 /* Bind it to the name. */
2851 memset(&sunaddr, 0, sizeof(sunaddr));
2852 sunaddr.sun_family = AF_UNIX;
2853 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
2855 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2856 packet_disconnect("bind: %.100s", strerror(errno));
2858 /* Restore the privileged uid. */
2861 /* Start listening on the socket. */
2862 if (listen(sock, 5) < 0)
2863 packet_disconnect("listen: %.100s", strerror(errno));
2865 /* Allocate a channel for the authentication agent socket. */
2866 nc = channel_new("auth socket",
2867 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2868 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2869 0, xstrdup("auth socket"), 1);
2871 error("auth_input_request_forwarding: channel_new failed");
2872 auth_sock_cleanup_proc(pw);
2873 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2877 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2881 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2884 auth_input_open_request(int type, u_int32_t seq, void *ctxt)
2887 int remote_id, sock;
2890 /* Read the remote channel number from the message. */
2891 remote_id = packet_get_int();
2895 * Get a connection to the local authentication agent (this may again
2898 sock = ssh_get_authentication_socket();
2901 * If we could not connect the agent, send an error message back to
2902 * the server. This should never happen unless the agent dies,
2903 * because authentication forwarding is only enabled if we have an
2907 name = xstrdup("authentication agent connection");
2908 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2909 -1, 0, 0, 0, name, 1);
2911 error("auth_input_open_request: channel_new failed");
2915 c->remote_id = remote_id;
2920 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2921 packet_put_int(remote_id);
2923 /* Send a confirmation to the remote host. */
2924 debug("Forwarding authentication connection.");
2925 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2926 packet_put_int(remote_id);
2927 packet_put_int(c->self);